Finding the Fourth Proportional to 1,018.77, 1,405.50 and 720.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.77 : 1,405.50 = 720.45 : x
2. Step 2: Convert to fraction form
   1,018.77/1,405.50 = 720.45/x
3. Step 3: Cross multiply
   1,018.77x = 1,405.50 × 720.45
4. Step 4: Simplify right side
   1,018.77x = 1,012,592.48
5. Step 5: Solve for x
   x = 1,012,592.48/1,018.77
6. Step 6: Final answer
   x = 993.94